I've seen Xhaka put in MOTM performances vs Bayern in the past, I don't think it's fair to say that he generally struggles against teams that press high up (certainly not Soton or United). First off those teams run a high risk themselves playing that way against him as he can play accurate long balls behind the last man and then how many players can you list that do enjoy being harrassed around on the pitch?
If he can bring a similar level to England that he had at Gladbach he'll be a massive asset for us. He's just 23 too, don't see what there is to sound depressed about. Needs to use his weaker foot more often though, this way he'll sadly fit in just nicely with the rest of the squad.